Oil leak on the back of an IO-360

[MV Aviation]

9 hours ago, Marauder said:

 

 

Marco - check at the base of the oil dipstick tube. Mine leaks there.


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The area around the dipstick base is dry. The oil traces start way above it.

[ArtVandelay]

The area around the dipstick base is dry. The oil traces start way above it.

Given you have 175 mph winds blow through the engine area with all sorts of stuff that can deflect or cause turbulent air flow, I would not assume anything, oil leaking from the bottom can end up on top, front to back, back to front.

[Browncbr1]

13 hours ago, jetdriven said:

The factory dipstick tube gasket is very thin, made of paper, and act of loosening the oil dipstick cracks the gasket loose and it's just a crappy design. But if you get a small O ring and install it on the dipstick tube, about a 1/16th of an inch wide version, and torque that down and safety wire it, it was withstand movement without leaking.  Mine has been dry for three years now.

for the benefit of the community, can you please share the part number for the oring you used for this?

[jetdriven]

I don't have it. But it's a 1/16" o-ring that fits snugly on the base of the dipstick tube below the threads. 

Is actually slightly smaller than the OD of the tube in that area and was stretched a little to fit on there  

 

Edited March 17, 2017 by jetdriven

[helitim]

The source of my most irritating oil leak turned out to be the oil return line.  The o-clamp had loosened over time.  Check all 4'cylinders while you're under there if you haven't already.

[MV Aviation]

Here's some footage I took after a flight:

looks like we gonna change the mag gasket and see if that fixes the issue.

 

[Guest]

50 minutes ago, MV Aviation said:

Here's some footage I took after a flight:

looks like we gonna change the mag gasket and see if that fixes the issue.

 

 

While you have the magneto off, relocate the engine ground bck to the governor drive adapter stud.

Clarence 

[jlunseth]

Don't forget the quick drain.  Drops on the nose gear are exactly where that shows up.  Every year at annual you should have your mechanic remove the quick drain and drain the oil through the big hole.  The quick drain should be flushed and it is a good idea to put a new seal kit in it every couple of years.  All it takes is a tiny piece of something swimming in the oil to cause the quick drain to fail to seal, and you can lose quite alot of oil when the engine is running and pressurized.  I once had an exciting landing because of it.

[Yetti]

I vote right mag.   And a note with video.   Find your shot.  Hold steady, count to 5.  Then move.  Repeat.

[carusoam]

Great video post MV.

Great advice followed the great video.

+1 on Yetti technique.

Best regards,

-a-

[MV Aviation]

SOLVED
Last week I did a 50h inspection and my mechanic found one of the right magneto screws to be loose. He checked the timing and fastened the screw. The leak is gone.

Thanks for all your input!

MV

[1964-M20E]

Glad to hear you figured it out.

Don't worry the oil will find a new place to escape it hates being trapped inside the engine.  Oil likes the view from the bottom of the plane better.

 

 

[carusoam]

MV,

great pirep.

-----------------

not sure if this applies, but it is worth checking on...

See if you have star washers on the mag screws (bolts). IIRC re-use of these parts doesn't work.  Get new washers and torque properly.

PP thoughts only, not a mechanic.

Best regards,

-a-

[GDGR]

Appreciate the notes on this. Noticed a small amount of oil on the passenger floor today. Thought it might have been a small spill (added a qt prior to flight). Wiped it up and a small amount showed up after a couple hours. At least this gives me a few ideas where to look for a leak. 

[tony]

7 hours ago, CDNflyby said:

Appreciate the notes on this. Noticed a small amount of oil on the passenger floor today. Thought it might have been a small spill (added a qt prior to flight). Wiped it up and a small amount showed up after a couple hours. At least this gives me a few ideas where to look for a leak. 

I assume you have the old style oil pressure indicator?

[GDGR]

3 hours ago, tony said:

I assume you have the old style oil pressure indicator?

Yes. It’s a basic old 74 M20F with few upgrades. So, steam gauges all around. 

[Andy95W]

2 hours ago, CDNflyby said:

Yes. It’s a basic old 74 M20F with few upgrades. So, steam gauges all around. 

If the small amount of oil is beneath your engine instrument cluster, you probably have a leaking oil pressure gauge or oil line.

If you lie on your back on the co-pilot seat with your head and shoulders on the floor you should be able to find your leak. You’ll need a good flashlight and trace the hose from the back of the gauge forward to the firewall. 

[GDGR]

2 minutes ago, Andy95W said:

If the small amount of oil is beneath your engine instrument cluster, you probably have a leaking oil pressure gauge or oil line.

If you lie on your back on the co-pilot seat with your head and shoulders on the floor you should be able to find your leak. You’ll need a good flashlight and trace the hose from the back of the gauge forward to the firewall. 

That actually makes perfect sense! I'm going to head out there this afternoon and see if I can't find it. There's an AME at the airport as well that I might employ, but would be nice to find the culprit myself. 

It's a small amount of oil, that puddled just aft of the passenger pedals....a line to the pressure gauge would make sense how it got inside the firewall, and dripping down onto the cabin floor. 

[jaylw314]

1 hour ago, CDNflyby said:

There's an AME at the airport as well that I might employ

 

Why would you need a aviation medical examiner to find an oil leak (in your plane, anyway)?    Good luck!

[Guest]

15 hours ago, CDNflyby said:

Appreciate the notes on this. Noticed a small amount of oil on the passenger floor today. Thought it might have been a small spill (added a qt prior to flight). Wiped it up and a small amount showed up after a couple hours. At least this gives me a few ideas where to look for a leak. 

Oil from refilling the engine would have a hard time finding its way into the cabin.  I would suspect that the oil line/hose from the firewall to the gauge is leaking.

I would suggest removing the instrument panel cover forward of the windshield for a closer inspection.

Clarence

Transport Canada AME, M1

[GDGR]

1 hour ago, jaylw314 said:

Why would you need a aviation medical examiner to find an oil leak (in your plane, anyway)?    Good luck!

LOL... oops... fast typing. Perhaps the AME is to fix my Cranial-Anal Insertion. 

[GDGR]

59 minutes ago, M20Doc said:

Oil from refilling the engine would have a hard time finding its way into the cabin.  I would suspect that the oil line/hose from the firewall to the gauge is leaking.

I would suggest removing the instrument panel cover forward of the windshield for a closer inspection.

Clarence

Transport Canada AME, M1

That was my initial thought as well. It was a small amount, so thought it possibly "filtered" through after some time. Didn't make sense to me though. Pressure Gauges do. Checking it out this afternoon. 

[Andy95W]

3 hours ago, M20Doc said:

 

I would suggest removing the instrument panel cover forward of the windshield for a closer inspection.

Clarence

Clarence makes a better point than I did- since you still have the original front windshield, you have the access panels on the top of the fuselage.  That will make it MUCH easier to find the leak rather than lying on your back under the instrument panel!

[GDGR]

8 hours ago, Andy95W said:

If the small amount of oil is beneath your engine instrument cluster, you probably have a leaking oil pressure gauge or oil line.

If you lie on your back on the co-pilot seat with your head and shoulders on the floor you should be able to find your leak. You’ll need a good flashlight and trace the hose from the back of the gauge forward to the firewall. 

You nailed it @Andy95W loose connection at the back of the oil pressure gauge. Took   Access plate in front of the window off, and was able to tighten from there, after removing the Tach for access. 

30 mins later, all good. 

Thanks for the advice  

 

[Guest]

7 minutes ago, CDNflyby said:

You nailed it @Andy95W loose connection at the back of the oil pressure gauge. Took   Access plate in front of the window off, and was able to tighten from there, after removing the Tach for access. 

30 mins later, all good. 

Thanks for the advice  

 

Glad you were able to locate the leak.  Was is a hose or metal line?  If a hose check for a metal ID tag with the manufacture date on it.  If a metal tube check it for abrasion and corrosion from contact with Scat air and defrost ducts.

Clarence